How Long Should It Take To "prepare" Before Burning

Hi,
I am trying to burn a disc image to a double layer DVD on Toast 8. It's been "preparing" for 30 minutes. When I hit abort, it says that if I continue to abort the process, I will no longer be able to use the disc. What do you think is wrong?
Thanks!

It might be that the optical drive has been put in sleep mode by lack of activity, and that the software is unable to wake it. If that is the case, then nothing is written to the disc and you may be able to use it again.

Anyway, 30 minutes is way to long for hoping that it will suddenly activate and continue.